function Tab(el) {
    this.el = document.querySelector(el)
    this.init()
}
Tab.prototype.init = function() {
    this.changeTitle()
}
Tab.prototype.changeTitle = function() {
    let ulLiObjs = this.el.querySelectorAll('ul li ')
    ulLiObjs.forEach((item, i) => {
        item.onmouseover = () => {
            this.el.querySelector('ul li.active').className = ''
            ulLiObjs[i].className = 'active'
            this.el.querySelector('ol li.active').className = ''
            let olLiObjs = this.el.querySelectorAll('ol li')
            olLiObjs[i].className = 'active'
        }
    })
}